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Background

The Woodland Township Route 532 and Route 72 sites are located in Woodland Township, Burlington County, New Jersey.

The Route 72 site is approximately 12 acres in size and is located 1/4 mile south of Route 72 along Crawley Road. Approximately 800 acres of wetlands, including cedar swamp, bog hardwood swamp, and pitch-pine lowland are located in close proximity to the Route 72 site. Pope Branch, an intermittent stream, is located approximately 500 feet to the north and 1,000 feet west of the site.

The Route 532 site is located approximately 3 miles from the Route 72 site. The Route 532 site is approximately 20 acres in size and is located at the end of an access road approximately 1/8 mile south of Route 532. The unnamed site access road meets Route 532 approximately 1 and 1/8 miles west of the intersection of Route 532 and Route 72. Goodwater Run, an intermittent stream, and Bailey Road border the Route 532 site to the east. An unpaved forest fire control road runs along the southern edge of the site. More than 200 acres of wetland including cedar swamp, bog, hardwood swamp and pitch-pine lowland are located downgradient of the former disposal area of the Route 532 site. Inactive commercial cranberry bogs are located approximately 1 mile west-southwest of the site.

Both sites were operated concurrently as chemical manufacturing waste disposal areas from the early 1950s until about 1962. At the Route 72 site, concrete pads, possible basements, a utility building, and sidewalks existed prior to disposal activities. Liquids, drums, and general refuse were disposed of in several excavated trenches. At the Route 532 site, a pine forest existed prior to the beginning of disposal operations. Liquids, drums, and general refuse were disposed into a series of bermed areas. By 1962, most of the disposal areas at both sites had been graded, and cover conditions were established.

The sites were placed on the National Priorities List September 21, 1984

A remedial investigation/feasibility study (RI/FS) was conducted in phases from 1985 through 1989. It was determined that soil at both sites was contaminated with volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs), and inorganics. The various contaminants include benzene, cresols, toluene, ethylbenzene, xylenes, polychlorinated biphenyls, arsenic, cadmium, chromium, lead, nickel, silver, and zinc. Groundwater was contaminated at both sites with VOCs, SVOCs and inorganics. The major contaminants include 1,2-dichloroethane (1,2- DCA), ethylbenzene, toluene, and xylenes.

What Has Been Done to Clean Up the Site?

EPA memorialized its selection of a remedy for the sites in a 1990 Record of Decision (ROD). The ROD addressed soil and groundwater contamination at the sites.

In 1990, approximately 37,200 cubic yards and 60,200 cubic yards of surficial and near surface materials from the Route 72 and 532 sites, respectively, were excavated, removed, and disposed of at an off-site facility. This effectively reduced the source of continuing groundwater impacts. After excavation and disposal of surface materials, the sites were graded and protective vegetative and mulch covers were set down to prevent soil erosion.

The groundwater remedy in the 1990 ROD required the extraction and treatment of groundwater from the fenced former disposal areas at both sites and of the downgradient plume at the Woodland Township Route 72 site. Monitored natural attenuation (MNA) was selected for the downgradient Woodland Township Route 532 site plume.

Subsequent environmental evaluations demonstrated that the degree of groundwater extraction required at the Woodland Township Route 72 site would cause groundwater drawdown in the Pineland wetlands and re-injection would raise groundwater levels upgradient of the site, resulting in adverse impacts to the sensitive Pineland ecology. Fourteen critical environmental and ecological resources that could be impacted by remediation of the sites were identified. Therefore, it was determined that groundwater extraction and reinjection would pose a more significant threat to the environment than the contaminant plume. Further studies identified air sparging and soil vapor extraction (AS/SVE) as a more appropriate groundwater remedy for the sites. On July 1, 1999, NJDEP issued a ROD Amendment to address the contaminated groundwater at the Route 532 and Route 72 sites. The major components of the modified remedy included the following:

• Groundwater in the former disposal areas at both the Woodland Township Route 532 and Route 72 sites would be remediated using an AS unit to inject air into the saturated zone and strip away volatile and semi-volatile organic compounds dissolved in groundwater and adsorbed to the soil, a SVE system to capture sparged vapors, and a vapor treatment system to treat the soil vapor extraction off gas.

• The downgradient portion of the plumes at both sites would be allowed to naturally attenuate while implementing a MNA program.

At the Route 532 site, an estimated 44,500 pounds of organic constituents were biodegraded, and another 1,600 pounds of VOCs were stripped from the subsurface by July 2005, when AS/SVE operations ceased. Annual monitoring of MNA wells shows that contaminant concentrations in groundwater are approaching GWRGs.

AS/SVE is complete at the Route 72 site Phase 1 area, an estimated 46,500 pounds of organic constituents were biodegraded, and another 2,960 pounds of VOCs were stripped from the subsurface through January 2007, when AS/SVE operations concluded. Sparging began in the Phase 2 area in 2003 and continued through 2009. Mass removal from the Phase 2 area was estimated at 81,400 pounds of organic constituents biodegraded in 2009. Biosparging continued from 2011-2012 in the Phase 2 expansion area, and then resumed in 2015.

Although surface soils were remediated in 1990, subsurface soils were not addressed in that action. Based on the data collected in a remedial investigation, NJDEP and EPA determined that no remediation was needed for the subsurface soils for both sites and a "No Further Action" ROD, with monitoring, was signed on September 28, 1993.

What Is the Current Site Status?

The soil remediation for the two sites has been completed. Groundwater concentrations of COCs continue to decline in the plume stability and sentinel monitoring wells. Although groundwater at the sites has not yet met the groundwater remedial goals, there are currently no receptors that could be exposed to groundwater and a Classification Exception Area and Well Restriction Area institutional control is in place to prevent the installation of drinking water wells in the contaminated plume.

Activity and Use Limitations

At this site, activity and use limitations that EPA calls institutional controls are in place. Institutional controls play an important role in site remedies because they reduce exposure to contamination by limiting land or resource use.
They also guide human behavior. For instance, zoning restrictions prevent land uses – such as residential uses – that are not consistent with the level of cleanup.

Security fencing surrounds the former disposal areas at both sites. A Classification Exception Area and Well Restriction Area are institutional controls that have been put in place for both sites. The Classification Exception Area suspends the designated original uses of the ground water beneath each site and the Well Restriction Area for each site has been established to prevent the use of ground water beneath the sites as potable water.

Sampling and Monitoring

Air Sparging/Soil Vapor Extraction - Route 72 Site

Due to the results of an expanded monitoring performed in September 2015, the biosparge system was reactivated in November 2015 as a Phase 3, to treat residual Toluene, Ethylbenzene and Total Xylenes (TEX) and reduce downgradient flow from the Phase 2 Area.

Performance monitoring in these areas was conducted quarterly throughout 2017.

Air Sparging/Soil Vapor Extraction - Route 532 Site

AS/SVE systems and unused monitoring wells were decommissioned in 2011 and 2012, respectively.

Monitored Natural Attenuation - Route 72 Site

• quarterly groundwater sampling at 21 Source Depletion wells for the first two years of the MNA program and semi-annually thereafter;

Enforcement Information

On March 4, 1985, NJDEP issued a directive to the Rohm and Haas Company, the Minnesota Mining and Manufacturing (3M) Company, Hercules, Inc., and other companies identified as potentially responsible parties (PRPs) to arrange for the investigation and remediation of the sites. On March 27, 1985, NJDEP entered into an Administrative Consent Order (ACO) with Hercules, Inc. to help pay for the investigative and administrative costs. On July 6, 1987, NJDEP entered into a similar ACO with 3M and Rohm and Haas Company.

On January 2, 1990, NJDEP entered into a Second Administrative Consent Order (ACO II) with Hercules, 3M and Rohn and Hass. The purpose of this ACO was to compel the PRPs to remove liquids and sludges from isolated locations on the site’s surfaces.

A third order, ACO III, was signed with Hercules, 3M and Rohm and Hass on June 15, 1990. It required the PRPs to excavate for off-site disposal all visibly contaminated surface soils from both sites, as specified in the OU1 ROD, dated May 16, 1990.